Solar Power and Water.  Desalination Can Be Powered by Solar Energy

U.S  President John F. Kennedy,  speaking in 1962,  said: ‘If we could produce fresh water from salt water at a low cost, that would indeed be a great service to humanity, and would dwarf any other scientific accomplishment.’ In the half century since, the need for innovation to satisfy humanity’s demand for clean water has become ever more urgent. While technological advances continue to improve the efficiency of desalination methods, it is vital that the sources of power used by desalination plants also continue to evolve.

An article by Robin Yapp  discusses Saudia Arabia’s ambitious plans to introduce  new solar-powered desalination plants.

The country’s Saline Water Conversion Corporation (SWCC) announced plans to establish three new solar-powered desalination plants in Haqel, Dhuba and Farasan.   SWCC is the biggest producer of desalinated water worldwide, accounting for 18% of global output.

Around half the operating cost of a desalination plant comes from energy use, and on current trends Saudi Arabia and many other countries in the region would consume most of the oil they produce on desalination by 2050.

The dominant desalination technology at present, with around 60% of global capacity, is Reverse Osmosis (RO), which pushes brine water through a membrane that retains the salt and other impurities.

Thermal desalination uses heat as well as electricity in distillation processes with saline feedwater heated to vaporise, so fresh water evaporates and the brine is left behind. Cooling and condensation are then used to obtain fresh water for consumption.

Desalination with renewable energy can already compete cost-wise with conventional systems in remote regions where the cost of energy transmission is high.

The use of solar power can bring huge cuts to the facility’s contribution to global warming and smog compared to use of RO or MSF with fossil fuels, according to the developers.

Around 700 million people in 43 countries are classified by the UN as suffering from water scarcity today,  but by 2025 the figure is forecast to rise to 1.8 billion. With the global population expected to reach nine billion by 2050 and the US Secretary of State openly discussing the threat of water shortages leading to wars, desalinated water has never been more important.